Method and apparatus for forming conical and related shapes



Jan; 1963 J. R. BIRCHFIELD ET AL 3,072,086

METHOD AND APPARATUS FOR FORMING CONICAL AND RELATED SHAPES Filed April 14, 1958 4 Sheets-Sheet 1 LIVE ILZQ 7"5 (/5192? E. Ba e/weld 2 Var/an A. fizz/aim Jan. 8, 1963v J. R. BIRCHFIELD ETAYI. 3,072,036

METHOD AND APPARATUS FOR FORMING CONICAL AND RELATED SHAPES Filed April 14, 1958 4 Sheets-Sheet 2 gig: Lye ILZUT'E Jan. 8, 1963 J. R. BIRCHFIELD ET AL 3,072,086

METHOD AND APPARATUS FOR FORMING CONICAL AND RELATED SHAPES Filed April 14, 1958 4 Sheets-Sheet 5 gg fi .ELL/E ZZZ-UTE dbfzzz Z8. Birch/422M Jan. 8, 1963 J. R. BIRCHFIELD ET Al. 3,072,086

METHOD AND APPARATUS FOR FORMING CONICAL AND RELATED SHAPES Filed April 14, 1958 4 Sheets-Sheet 4 Egn j he flzbr's cfa/m E. Eire/2292M Var/a2; A. Gu/amzl United States Patent 3,072,ti86 METHOD AND APPARATUS FQR FORMiN-G (IONICAL AND RELATED SHAPES John R. Birchtield, Wiclrlifie, and Vartan A. Gulaian, East (Ileveland, Ohio, assignors to Thompson Ramo Wooldridgc, Inc., a corporation of Ohio Filed Apr. I4, 1958, Ser. No. 723,260

8 Ciainrs. (El. 1l3--52) The present invention relates broadly to the art of metal forming, and is more particularly concerned with a novel method and apparatus for shaping essentially fiat metal surfaces into conical and related configurations.

Hollow metallic bodies of general conical configuration are employed in various applications, and a typical environment for such shapes is in rocketry as the nose section of an airborne article. The preferred practice is to form the conical member by shear spinning, which is also referred to in the art by the terms of roll forming, hydro-spinning, floturning, rotary extruding and spin forging.

However, present techniques of spinning by use of rotating shaped mandrels have been deficient since it has been impossible to produce a true conical article thereon. One approach heretofore taken has been to utilize a blank provided with a central opening, and after imparting an openended generally conical shape thereto, suitably secure a pointed tip to the shape. An alternative method often employed is to form a solid fiat blank into a frustro-conical configuration, remove the closed end from the shape thus formed, and thereafter attach a conical tip thereto. The deficiencies of each of these laborious methods of producing a sharp-pointed conical article are immediately apparent to those versed in the art.

It is therefore an important aim of the present invention to provide methods of forming conical shapes in which the tip or vertex portion is formed integrally with the main body portion thereof.

Another object of the invention lies in the provision of apparatus by means of which a metal body of generally conical configuration having an integral nose portion may be shaped without resort to prior art welding and similar techniques.

Another object of this invention is to provide a sheet metal forming method and means constructed to impart a generally conical shape to a single blank essentially entirely by metal drawing or spinning techniques.

A further object of the invention lies in the provision of a relatively simple and effective means upon which a metal shape may be essentially simultaneously spun and moved axially to form the same into conical and related configurations.

A further object of the present invention is to provide a mandrel structure of the configuration finally desired on the blank to be formed and which is axially movable while supporting the blank for rotative movement thereon.

Other objects and advantages of the invention will become more apparent during the course of the following description. particularly when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to desi nate like parts throughout the same:

FIGURE 1 is a side elevational view of a mandrel arrangement upon which a metal blank may be initially formed;

FIGURES 2 and 3 are sectional views of the mandrel of FIGURE 1, and showing successive steps in the initial formin of the conical shape thereon;

FIGURE 4 is a side elevational view, partly in section, and showing a mandrel construction upon which the partially formed shape from FIGURE 3 may be finished into a sharp-pointed conical configuration:

3,072,086 Patented Jan. 8, 1963 FIGURES 5 and 6 are sectional views of the mandrel structure of FIGURE 4, and showing successive steps of forming the shape thereon;

FIGURE 7 is a sectional view of a modified form of mandrel drive means;

FIGURE 8 is a sectional view of another embodiment of the invention, illustrating a mandrel and slidable carrier arrangement by means of which a flat metal blank may be initially formed;

FIGURES 9 and 10 are views in section of the same structure as in FIGURE 8, and showing successive steps in the step of FIGURE 10;

FIGURE 11 is a side elevational view, partly in section, and showing a mandrel construction upon which the partially formed shape from FIGURE 10 may be finished in accord with the present invention; and

FIGURES 12 and 13 are views in section of the mandrel arrangement of FIGURE 11, illustrating the manner of successively forming a conical shape to the final configuration desired.

Briefly stated, the invention herein disclosed is practiced by arranging a sheet metal shape having an essentially fiat face in abutment with an axially immovable rotatable cone-shaped forming surface, the mid-point or center of the fiat face coinciding with the central axis or generatrix of the conical forming surface. The forming surface is splined or otherwise secured to a rotatable shaft carrying thereon an axially movable member to which the periphery of the sheet metal shape is attached. To assure relatively free axial movement of said member, it is preferred to employ a helical splined shaft or straight recirculating ball splined shaft. Rotative movement of the shaft causes simultaneous rotation of the sheet metal shape and travel of the axially movable member to form said shape to a final conical configuration having a relatively sharp vertex produced by the cone-shaped forming surface. Specific details of the additional novel features of the present inevntion will be particularly pointed out as the description proceeds.

Referring now to the drawings, and first to FIGURES 1 to 3, there is shown a structural embodiment effective to initially form an essentially flat metallic sheet into a generally frustro-conical shape, which is subsequently processed into a sharp-pointed cone configuration employable as produced for rocket noses, fixtures and the like. A lathe-type mechanism of conventional construction utilized in the shear spinning art may provide the supporting and motivating functions of the arrangement of FIGURES l and 3, and as shown therein, a mandrel 20 of essentially frustro-conical shape provided with a radially outwardly extending flange face 21 is secured to a face plate 22 forming a part of the lathe head stock portion generally designated by the numeral 23.

The head stock portion 23 is normally constructed to include a driven shaft 24 threaded at one end to receive a collar portion 25 of the face plate 22, and upon which is carried an annular spacer 26 hearing against a pulley 27 positioned in abutment to a flange port ion 28 on a relatively large diameter portion 29 of the head stock 23. Rotative movement for the spinning operation is imparted to the head stock and the mandrel 20 secured thereto by a belt 30 trained over the pulley 27 and connected to a suitable power source.

The mandrel 20 presents a right frusto-conical configuration in the form shown; however, conical shapes of the ogive type and others are within the contemplation of this invention, as well as certain other geometrical forms requiring a relatively sharp terminex and susceptible to shear spinning techniques as herein disclosed. The mandrel construction may vary within the skills of those versed in the art, and accordingly, may be essentially solid throughout, or may be provided with a conical cavity 31 therein as appears in FIGURES 2 and 3. Further, the composition of the mandrel may be steel, or for certain applications aluminum alloys and the like, and reinforced plastics may be found suitable, depending upon the strength and gauge of the material to be formed thereon.

- In any event, however, the mandrel 20 is freely supported at one end by reason of securement of its base 21 to the face plate 22. The base 21 and plate 22 are attached in face-to-face relation, each presenting an essentially flat surface, and bolts or similar meanstnot shown) may beemployed for this purpose. Opposite the base 21 the mandrel is provided with an essentially flat face or end surface 32,, the plane of which is generally parallel to the base to present a frusto-conical shaping surface.

Against the flat end face 32 of the mandrel is located a blank 33 to be formed, and the means to maintain said blank in-tight abutment with said face is preferably a pressure pad 34 or its equivalent against which an axial force is applied by a tail stock portion 35 of the lathe mechanism. The pressure pad is preferably arranged with its mid-point or center in alignment withthe radial center of the blank 33, or stated otherwise, all portions of the assembly shown in FIGURE 1 are axially arranged upon a common horizontal center line to assureproduction of a shape conforming to the exact contours of the mandrel 20.

To provide aright frusto-conical shape, for which the mandrel of FIGURE 1 was particularlyv designed, the blank 33 is essentially circular. However, variations from a straight or right conical configuration will, of course, normally demand a blank of other than a round circumference. The material of, the blank or workpiece will vary depending upon the end application, and in addition to sheet materials of aluminum, steeland the like, it is pos s'ible to shape partially cured thermosetting resins into sharp-pointed cones utilizing the principles of this invention. Further, a fully cured resin, such as phenol formaldehyde, may be shaped to conform to the contours of themandrels herein disclosed by applying heat to said mandrels and by use of post-forming techniques known to the art. The most important present application of this,

invention, however, lies in the spinning of sheet metal parts.

Rotation of the shaft 24 causes similar movement of the mandrel 20 and blank 33 positioned thereagainst, and to conform said blank in an extruding manner to the contours of the mandrel, a pressure surface 36 is applied thereto as appears in FIGURES 2 and 3. This surface may, be in the form of a free rotating wheel carried upon a shaft 37 supported at its opposite end upon the lathe mechanism for circumferential travel about the mandrel.

20. The path of travel of the pressure wheel 36 is preferably begun ata point on the blank 33 between the outer diameters of. the mandrel flat face 32 and pressure pad 34,- and designated generally by the legend a. The travel of the wheel or surface conforms to the contour of the mandrel 20 and proceeds. both circumferentially thereabout in pressing contact with the blank and longitudinally thereacross to extrude the original metal thickness by kneading operation whereby said metal is spread along the mandrel contours and the thickness thereof reduced Viewing again FIGURE 2, it may be seen that during rotative movement of the mandrel 20 and the blank 33 securedthereto, the pressure wheel 36 by its circumferential and longitudinal travel rolls rearwardly and extrudes aportion b of generally the original thickness of said blank until substantially the entire contour of the mandrel has been traversed and metal contact made with a ledge or forward surface 38 of the mandrel base 21. Formed by 4 this action is a lip or flange c on the frustro-conical shape 39 ofFIGURE 3.

The shape 39, as obtained from the last described preliminary forming step, is further characterized by an end wall or surface 0! of essentially the same thickness as the blank material 33, and of the same generally flat configuration as the end face 32 of the mandrel 20. Many applications require that the conical shape have a sharp-pointed nose portion, and one prior art practice has been to remove the end surface d by a cutting operation, and weld or otherwise secure a separately formed nose portion to the open-ended frustro-conical shape. This practice, as well as the other earlier mentioned conventional approach of employing a blank with a central opening therein, are clearly not economical from a time and material standpoint.

Applicants have discovered that the entire body of a sharp-pointed conical shape may be formed by extruding or drawing techniques, and apparatus of proven effectiveness in finally shaping the article of FIGURE 3 is illustrated in succeeding four views of the present drawings. Turningnow particularly to FIGURE 4, there is again employed a conventional lathe mechanism having a head' stock assembly 23 as described in connection with FIG- URE l, and like numerals designate this portion appearing in FIGURE 4. There is provided in this embodiment of the invention a helically threaded shaft 4% supported by an integral collar 41 upon the shaft 24 of the head stock portion 23 and rotatable therewith. Formed at the opposite end of the helical shaft 40 is an axially immovable conical shaping surface 42, and axially movable upon the shaft 40 is a mandrel 4-3 of generally frustro-conical' configuration.

It is of importance that discontinuities be prevented in the shape of the final article produced by practice of the steps illustrated in FIGURES 4, 5 and 6, and it has been found in this connection that relatively free axial movement of the sliding mandrel 43 is required. Astraight splined shaft is characterized by heavy bearing forces on the driving contact faces ofthis type shaft, with the result that relatively heavy friction resists axial movement of the mandrel. It is for this reason that a helical splined shaft as shown in the drawings is preferred, although as will be noted when reference is madeto FIGURE 7, a straight recirculating ball spline also provides an effective solution in accomplishing free axial movement. The angle of the helical spline or continuous buttressthread 44 on the shaft 40 is designed to give a controlled and uniform axial force to the mandrel 43 by contact with a continuous mating groove 45 out along the inner diameter of said mandrel. The angle and finish of the spline 44 substantially eliminate the heavy resistant friction between the groove 45 and the spline 44 to allow the mandrel 43 to rotate slower than the shaft 40 and move axially thereof.

The mandrel 43 is preferably of a solid and durable metallic construction, and one of the hardened steels is suitable for the present purposes The shape of the man drel is frustro-conicahas shown, and includes a generally flat end surface 46 disposed in parallel relation to a radially outwardly extending base flange 47 formed integral with the opposite end of the mandrel. In its extreme or starting position upon the splined shaft 40, the mandrel 43 abuts against the cone-shaped forming portion 42 of the said shaft by contact between the end, surface 46 of the mandrel and a ledge 48 on the cone-shaped portion 42.

The partially formed shape 39 from the step of FIG- URE 3 is mounted upon the axially stationary mandrel or cone-shaped surface 42 and axially movable mandrel 43 in the manner shown in FIGURE4. The center or mid-point of the end surface or relatively flat face d of the shape 39 bears against the vertex 49 of the cone-shaped forming portion 42, and the flange c of the said shape 39 abuts against a ledge or stepped portion 50 provided at the junction of the main body portion of the mandrel 43 and the flange 47 thereof. Clamp means 51 are pro vided to secure the frustro-conical shape 39 to the mandrel 43. The clamp means may be of the ring-type, or may be in the form of individual clamping members spaced circumferentially around the mandrel flange 47.

Power from a suitable source transmitted through the belt 30 to the pulley 27 of the head stock 23 causes rotation of the helical splined shaft 46 and cone-shaped mandrel portion 42 integral therewith. By reason of the helical spline configuration of the shaft 40, the mandrel 43 moves freely axially thereupon. Since the frustoconical shape 39 is firmly attached to the mandrel 43, rotative force applied to the splined shaft 40 causes rotation of the shape 39 and mandrel 43, although at a substantially lesser speed than the shaft 40. This arises by provision of the helical spline, and due to its relatively lesser rotative speed, the mandrel 43 moves axially along the shaft 40 in the manner of FIGURES and 6 to spin and extrude the blunt nose portion or flat end surface d to the thinness desired, and assure conformance of the fiat end surface to the contours of the rotating coneshaped forming surface or mandrel 42, the pressure surface 36 is provided. During this forming operation, the metal of the end surface d radially'outwardly of its center is deflected or drawn to a relatively lesser thickness, as appears in FIGURE 6, and as the mandrel 43 approaches the end of its axial travel, the entire body or shape 39 is extruded or drawn to a uniform wall thickness, as appears in FIGURE 6.

As will be appreciated, the contours and lengths of the axially stationary mandrel 42 and axially movable mandrel 43 may be altered to provide a shape different from that shown in the drawings, and the length of the helical splined shaft 40 modified to similarly effect desired changes in the configuration of the ultimate article produced. Further, it may be found desirable upon occasion to apply a live center cone to the sharp point or vertex 4? of the forming surface 42 during the course of performance of the steps illustrated in FIGURES 5 and 6 to prevent deflection of the mandrel and resist the load applied by the shear spinning tool.

Free axial movement of the mandrel 43 upon the splined shaft 40 has been found to prevent discontinuities in the shape of the finished piece as formed by the final shaping step of FIGURE 6. While successful results have been obtained in practice with the structural embodiment of the present invention illustrated in FIG- URES 4, 5 and 6, particularly conditions may indicate the desirability of also applying a tensile force to the frustro-conical shape 39 during the forming operation as a further assurance that a smooth contour will be achieved in the final article. Further, as a substitute for a helical splined shaft there may be employed a straight recirculating ball spline, and a construction of this character is shown in FIGURE 7. In this embodiment of the invention, a mandrel 56 moves axially in rolling contact with a plurality of round elements or ball 53 traveling in continuous grooves 54 formed in a shaft 55. The spline of FIGURE 7 is relatively straight, and in the event that slight axial resistance to movement is encountered under certain conditions, spring means or hydraulic force may be used to maintain the desired tension on the shape or workpiece 39. Rotation of the shaft 55 causes relatively slower rotative movement of the mandrel 56 upon the revolving and circumferentially traveling ball elements 53, and due to its relatively lesser speed of rotation, the mandrel 56 moves axially upon the shaft 55 to shear spin the shape 39 onto the conical forming surface 56a and into essentially the same configuration shown in FIGURE 6. Recirculating ball constructions are known to the art, and a plurality of ball elements 53 are arranged in the grooves 54 spaced circumferentially around the shaft 55 in accordance with customary practice.

-- Itmay be seen from the foregoing description, directed to the structural arrangements of FIGURES l to 7, that the shaping process is performed by first shear spinning a relatively flat blank into a frustro-conical shape and thereafter by flow extrusion or shear spinning shaping the frustro-conical article into the shape of the nature of a. right circular cone. While this process and apparatus have substantial advantages over the prior art, applicants have also discovered that a conical shape having a relatively sharp nose portion may be formed continuously from a flat sheet metal blank. An illustrative embodiment of this form of the present invention is illustrated in FIGURES 8, 9 and 10, and specific reference is now made thereto.

Essentially, in this form of the invention there is provided an internally splined tubular mandrel member 57 axially and rotatively movable upon a helically splined shaft 58 supported upon a head stock portion 23 of essentially the same construction shown in FIGURES 1 and 4. At its opposite end the shaft 58 :is formed with a cone-shaped mandrel portion 59 of essentially the same configuration shown in FIGURE 4. The tubular car-- rier. 57 is provided at one end with a radially outwardly extending flange portion 60 and against said portion a sheet metal blank 61 is secured along its periphery by clamp means 62.

The blank 61 is of essentially circular configuration, and is secured to the tubular member 57 with its radial center bearing against the vertex 63 of the conical shaping surface 59, and accordingly, the horizontal axis of the conical mandrel portion 5h, will be found to pass through the center of said blank.

The tubular member 57 is provided along its inner diameter with a continuous helically-shaped groove 64 receiving during travel of said member a similarly shaped continuous thread 65 formed on the outer diameter of the shaft 58. The tubular member or carrier 57 and shaft 58 are accordingly of the same spline, and the helical arrangement shown has been found in actual practice to assure free axial movement of the tubular carrier on the shaft. It is to be anticipatedthat a straight spline would be disadvantageous in this application because of the heavy bearing forces on the driving contact faces, and the heavy friction which would result to resist axial movement of the slidable tubular member 57. As in the earlier described embodiment of the invention, a straight recirculating ball spline could be employed as a substitute for the helical spline of FIGURES 8, 9 and 10. In addition, should particular conditions require that additional axial force be applied to conform the blank 61 to the precise contours of the cone-shaped forming surface 59, spring means or hydraulic cylinders or other equivalent arrangements may be employed.

A noted, the shaft 58 is supported at one end by the head stock portion 23 of a lathe mechanism, and rotative force is applied thereto by belt means 30 connected to a suitable power source. Rotation of the helical spline shaft 58 causes a reduced speed rotation of the tubular member 57 and sheet metal blank 61 attached thereto, and an axial movement of said tubular member or carrier rearwardly along the splined shaft 58 to shear spin the blank 61 upon the sharp-pointed axially immovable mandrel 59. To extrude the sheet metal of the blank to the thinness desired, and assure conformance of all portions of the blank to the mandrel contours, a pressure surface 66 of the same character shown in FIGURES 2 and 3 is preferably employed. This may again comprise a wheel mounted upon a shaft 67 and associated with the lathe mechanism for free rotation axially and circumferentially upon the blank being formed to the contour of the mandrel 5%. Travel of the pressure surface or wheel 66 is initiated radially outwardly of the blank midpoint and generally at the location identified by the legend e in FIGURE 8.

As the mandrel 59 is spun rotatively and the pressure surface 66 caused to travel thereabout, axial movement of the tubular carrier 57 with the blank 61 attached thereto spins or draws the blank into exact conformance with the contours of the mandrel 59, as shown in FIG- URE 9, and the progressive spinning operation continues until the carrier reaches the end of its path of axial travel. The portion or periphery of the blank 61 clamped to the collar or flange 60 of the carrier 57 remains attached thereto, and there is formed at the base of the shape 68 a radially extending flange f, as shown in FIGURE 10.

The flange f may be reduced in diameter or entirely trimmed from the shape 68, and said shape utilized as a rocket nose or the like. The article produced by practice of the invention shown in FIGURES 8, 9 and 10 is essentially a right circular cone, and it will be appreciated that by changes in the shape of the mandrel 59, other types of conical shapes may be produced. However, it is to be noted that there is now provided a continuous shaping operation whereby the final article desired is obtained without resort to independent forming operations and welding steps, as has characterized the prior art approaches.

In certain cases it may be found that the base diameter of the shape 68 is greater than desired, and to reduce this diameter said shape may be transferred to a mandrel construction of the character shown in FIGURES 11, 12 and 13. As appears therein, the shape 68 may be held against the vertex of a conically-shaped mandrel 69 by means of a formed pressure pad 70. The mandrel 69 is provided with a radially extending base flange 71, and is carried at one end by the head stock portion 23 of a conventional lathe mechanism in the same manner as earlier described. A free rotating pressure surface '72 carried upon a shaft 73 associated with the lathe mechanism is provided for axial and circumferential travel about the shape 68 to shear spin the flange 1 into contact with the contours of the mandrel 69 in essentially the manner shown in FIGURES 12 and 13. During this particular shear spinning operation, the flange 1 is extruded by the kneading action of the pressure surface 72 continuously rearwardly along the mandrel 69 until contact is made with the base flange 71 of said mandrel 69 During this secondary shaping operation, the base diameter of the shape 68 is reduced and the body of said shape substantially elongated to provide the final shape 74 of FIGURE 13.

It may be seen from the foregoing that applicants have provided mandrel arrangements and shaping methods. which entirely avoid each and every noted disadvantage of the prior art procedures. Each mandrel disclosed is of relatively simple construction, and the results obtained therefrom are of predictable and extremely close accuracy. By simultaneously applying rotative and axial movement to the relatively flat blank, all portions are evenly and continuously extruded into close fitting contact with the cone-shaped mandrel portion of the splined shaft. The apparatus disclosed is capable of various modifications, as by use of a straight recirculating ball spline, and for particular applications, the addition of means to exert a more positive axial force upon the blank to be formed. A wide variety of shapes may be produced, and materials of different compositions and thicknesses may be readily formed thereon.

It is to be understood that the forms of the invention herein shown and described are to be taken as preferred embodiments of the same, and that various changes and modifications may be effected in the size, shape and arrangement of parts without departing from the spirit of the invention or the scope of the subjoined claims.

We claim as our invention:

1. Apparatus for forming essentially conical shapes, comprising a splined shaft supported at one end and provided at its opposite end with a conical shaping member, a mandrel member having a flange at one end and threadably mounted upon the shaft for circumferential and axial traveltherealong, means for clamping a generally fiat circular surface to the mandrel flange with. the radial center of said surface abutting the vertex of the conical shaping member, and means mounted on the apparatus for simultaneously rotating the shaft and moving the mandrel therealong to rotate the surface and axially extrude the same into conformance with the contours of the conical shaping member.

2. Apparatus for forming essentially conical shapes, comprising a splined shaft supported at one end and provided at its opposite end with a conical shaping member, a substantialiy frustro-conical shaped mandrel member threadably mounted upon the shaft for axial travel therealong and having a base flange, means for clamping the base of a preformed frustro-conical metal shape to the base of the mandrel member, and means rotating the shaft and essentially simultaneously moving the mandrel member and shape attached thereto axially away from the conical shaping member to spin the shape into contact therewith.

3. Apparatus for forming essentially conical shapes, comprising a splined shaft supported at one end and provided at its opposite end with a conical shaping member, a tubular mandrel member threadably carried by the shaft for free axial movement therealong, means attaching the periphery of a disk blank to one end of the tubular member with its radial center abutting the vertex of the conical shaping member, and means rotating the shaft, conical member and blank and essentially simultaneously axially moving the mandrel member to extrude the disk blank against the conical member.

4. Apparatus for forming essentially conical shapes, comprising a substantially straight splined shaft and a plurality of recirculating ball elements movable therealong, a mandrel member threadably mounted upon the shaft in contact with the ball elements and axially movable along the path of travel of the ball elements, a conical shaping surface integral with one end of the shaft, a generally circular blank positioned in contact with the conical shaping surface, means clamping the blank to the mandrel member, and means rotating the shaft and essentially simultaneously moving the mandrel member along the path of travel of the ball elements to spin the blank into conformance with the contours of the conical shaping surface.

5. Apparatus for forming essentially conical shapes, comprising a substantially straight splined shaft and a plurality of recirculating ball elements movable therealong, a generally frustro-conical mandrel member threadably mounted upon the shaft in contact with the ball elements and axially movable along the path of travel of said elements, a conical shaping surface integral with one end of the shaft, a substantially frusto-conical metallic shape supported upon the mandrel member with its end wall in contact with the conical shaping surface, and means rotating the shaft and essentially simultaneously moving the mandrel member along the path of travel of the ball elements to spin the end wall of the shape into conformance with the contours of the conical shaping surface.

6. Apparatus for forming essentially conical shapes, comprising a threaded shaft supported at one end and provided at its opposite end with a conical shaping member, a mandrel member threadably carried by the shaft for free axial movement therealong, means for securing a workpiece with a generally flat circular surface to the mandrel member with its radial center in contact with the vertex of the shaping member, and means mounted on the apparatus for rotating the shaft and circular surface and means for pressing the fiat surface against the conical shaping member whereby said mandrel member will move axially away from the conical shaping member and pull said workpiece to accommodate conforming of said surface to the shape of said member.

7. The method of making cone shapes from workpieces having non-conical surfaces which comprises, threading a comically nosed shaft through an axially shiftable mandrel, securing the periphery of a workpiece to said axially shiftable mandrel with the shaft nose bottomed on the central portion of said surface of said workpiece, driving the shaft to rotate the mandrel and workpiece, pressing a pressure surface against said rotating workpiece surface for spinning the surface toward the nose, simultaneously rotating the threaded mandrel relative to the shaft for moving the mandrel axially away from the nose, and pulling the periphery of the workpiece with the axially shifting mandrel for drawing the workpiece into conformity with the nose.

8. Apparatus for forming essentially conical shapes, comprising a threaded shaft supported at one end and provided at its opposite end with a conical shaping memher, a tubular mandrel threadably carried by the shaft for free axial movement therealong, means for securing a workpiece with a generally flat circular surface to the mandrel member with its radial center in contact with the vertex of the shaping member, means to rotate the shaft, a pressure wheel mounted to press the flat surface against the conical shaping member, and said pressure wheel causing relative rotation between said mandrel and said shaft 10 during the rotation of said shaft whereby the mandrel will move axially away from the conical shaping member and pull the workpiece to conform to the shape of the conical shaping member.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Knights American Mechanical Dictionary, vol. III, page 2280, published by Houghton, Mifilin, and Co., The Riverside Press, Cambridge, Massachusetts, published Metals Handbook, 1948 edition, page 6, The American Society for Metals. 

1. APPARATUS FOR FORMING ESSENTIALLY CONICAL SHAPES, COMPRISING A SPLINED SHAFT SUPPORTED AT ONE END AND PROVIDED AT ITS OPPOSITE END WITH A CONICAL SHAPING MEMBER, A MANDREL MEMBER HAVING A FLANGE AT ONE END AND THREADABLY MOUNTED UPON THE SHAFT FOR CIRCUMFERENTIAL AND AXIAL TRAVEL THEREALONG, MEANS FOR CLAMPING A GENERALLY FLAT CIRCULAR SURFACE TO THE MANDREL FLANGE WITH THE RADIAL CENTER OF SAID SURFACE ABUTTING THE VERTEX OF THE CONICAL SHAPING MEMBER, AND MEANS MOUNTED ON THE APPARATUS FOR SIMULTANEOUSLY ROTATING THE SHAFT AND MOVING THE MANDREL THEREALONG TO ROTATE THE SURFACE AND AXIALLY EXTRUDE THE SAME INTO CONFORMANCE WITH THE CONTOURS OF THE CONICAL SHAPING MEMBER. 